<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Frontend
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Function.php 18951 2009-11-12 16:26:19Z alexander $
 */


/**
 * @see Zend_Cache_Core
 */
require_once 'Zend/Cache/Core.php';


/**
 * @package    Zend_Cache
 * @subpackage Zend_Cache_Frontend
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Cache_Frontend_Function extends Zend_Cache_Core
{
	/**
	 * This frontend specific options
	 *
	 * ====> (boolean) cache_by_default :
	 * - if true, function calls will be cached by default
	 *
	 * ====> (array) cached_functions :
	 * - an array of function names which will be cached (even if cache_by_default = false)
	 *
	 * ====> (array) non_cached_functions :
	 * - an array of function names which won't be cached (even if cache_by_default = true)
	 *
	 * @var array options
	 */
	protected $_specificOptions = array(
        'cache_by_default' => true,
        'cached_functions' => array(),
        'non_cached_functions' => array()
	);

	/**
	 * Constructor
	 *
	 * @param  array $options Associative array of options
	 * @return void
	 */
	public function __construct(array $options = array())
	{
		while (list($name, $value) = each($options)) {
			$this->setOption($name, $value);
		}
		$this->setOption('automatic_serialization', true);
	}

	/**
	 * Main method : call the specified function or get the result from cache
	 *
	 * @param  string $name             Function name
	 * @param  array  $parameters       Function parameters
	 * @param  array  $tags             Cache tags
	 * @param  int    $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
	 * @param  int   $priority         integer between 0 (very low priority) and 10 (maximum priority) used by some particular backends
	 * @return mixed Result
	 */
	public function call($name, $parameters = array(), $tags = array(), $specificLifetime = false, $priority = 8)
	{
		$cacheBool1 = $this->_specificOptions['cache_by_default'];
		$cacheBool2 = in_array($name, $this->_specificOptions['cached_functions']);
		$cacheBool3 = in_array($name, $this->_specificOptions['non_cached_functions']);
		$cache = (($cacheBool1 || $cacheBool2) && (!$cacheBool3));
		if (!$cache) {
			// We do not have not cache
			return call_user_func_array($name, $parameters);
		}
		$id = $this->_makeId($name, $parameters);
		if ($this->test($id)) {
			// A cache is available
			$result = $this->load($id);
			$output = $result[0];
			$return = $result[1];
		} else {
			// A cache is not available
			ob_start();
			ob_implicit_flush(false);
			$return = call_user_func_array($name, $parameters);
			$output = ob_get_contents();
			ob_end_clean();
			$data = array($output, $return);
			$this->save($data, $id, $tags, $specificLifetime, $priority);
		}
		echo $output;
		return $return;
	}

	/**
	 * Make a cache id from the function name and parameters
	 *
	 * @param  string $name       Function name
	 * @param  array  $parameters Function parameters
	 * @throws Zend_Cache_Exception
	 * @return string Cache id
	 */
	private function _makeId($name, $parameters)
	{
		if (!is_string($name)) {
			Zend_Cache::throwException('Incorrect function name');
		}
		if (!is_array($parameters)) {
			Zend_Cache::throwException('parameters argument must be an array');
		}
		return md5($name . serialize($parameters));
	}

}
